Modeling of germanium atomic-layer-epitaxy

Atomic-layer-epitaxy (ALE) of germanium has been analyzed by a kinetic model and a thermodynamic model. Chlorogermanes are found to be unsuitable since they cannot satisfy the self-limiting adsorption condition due to quick thermal desorption of HCl from the surface. On the other hand, the ideal growth rate of one monolayer per cycle is expected for dimethylgermane. This is because there exists no recombinative desorption reaction between surface methyl groups and H that will break the self-limiting adsorption condition. It has also been confirmed, from thermodynamic considerations, that the elemental chemical reactions used in this ALE, i.e., self-limiting adsorption and reduction of surface methyl groups by atomic hydrogen, are spontaneous.